The effect of segmented metal plane in microstrip structure

When the ground plane of a multi-layered PCB (microstrip structure) is partly segmented under a signal strip, the radiated emission of the structure significantly increases. We model several cases which can be typical structures in PCBs and calculate those cases of the segmented structures with a method of moments based electromagnetic simulator. The experiments were followed with generic type antennas and a semi-anechoic chamber; the results are very useful for EMC designers to make actual PCB designs.